Rock and Mineral pot

Eye Wonder 4-5 Rocky Earth 6-7 A volcanic beginning 8-9 Making of a rock 10-11 Igneous rock 12-13 Sedimentary rock 14-15 Metamorphic rock 16-17 Rocks from space 18-19 Hidden beauty 20-21 Breakdown 22-23 Carving a path 24-25 Crystals 26-27 What a gem! LONDON, NEW YORK, MUNICH, MELBOURNE, and DELHI Contents First published in Great Britain in 2004 by Dorling Kindersley Limited 80 Strand, London WC2R 0RL 2 4 6 8 10 9 7 5 3 1 A Penguin Company Copyright © 2004 Dorling Kindersley Limited, London A CIP catalogue record for this book is available from the British Library. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the copyright owner. ISBN 1-4053-0090-6 Colour reproduction by Colourscan, Singapore Printed and bound in Italy by L.E.G.O. see our complete catalogue at www.dk.com Written and edited by Caroline Bingham Designed by Helen Chapman Publishing manager Susan Leonard Managing art editor Clare Shedden Jacket design Chris Drew Picture researcher Sarah Stewart-Richardson Production Shivani Pandey DTP Designer Almudena Díaz Consultant Kim Dennis-Bryan PhD, FZS With thanks to Victoria Long for design assistance. 28-29 Precious metals 30-31 Get that metal! 32-33 Using rocks in art 34-35 Rocks in history 36-37 Building rocks 38-39 A touch of mystery 40-41 History in a rock 42-43 Hunting for rocks 44-45 What does it make? 46-47 Glossary 48 Index and acknowledgements 4 c a r c o m p u t e r c l o t h e s t e l e p h o n e j e w e l l e r y y o u a n d m e ! house Rocky Earth Rocks and minerals are important. They make up much of our planet and are mined to provide many of the things around us, from cars to computers. Even your body contains minerals that keep you alive. t o o t h p a s t e Store cupboard The things we use in our everyday lives come from our planet, Earth. The raw ingredients are all taken from the crust. We cannot drill any deeper. Most of the crust and mantle is made from lots of different rocks, all squashed together. 5 Let’s make a rock Rocks are made up of crystals of minerals. Different amounts of minerals make up different rocks (though some rocks are made from just one mineral). Let’s make shampoo What forms the shampoo you use on your hair? Minerals, including those below! Earth’s crust is between 5 and 68 km (3 1 ⁄2 and 42 miles) thick. Quartz (grey) Scientists believe the Earth was born about 4,600 million years ago. ++ = + + = quartz crystals feldspar crystals mica crystals granite (a type of rock) coal tar lithium clay selenium shampoo M a n t l e E a r t h ’ s c r u s t O u t e r c o r e C o r e Mica (black) Feldspar (pink and white) • Your body contains more than 60 minerals. Nine of these are essential for life. • Some minerals take thousands of years to form. Some form in minutes. Mineral facts Squeeze clay in your hands and it oozes between your fingers. This is a little like what happens inside a volcano. The pressure grows until the volcano erupts. Whoosh! It is the first step in the formation of new rocks. A volcanic beginning T h e m a g m a i s f o r c e d u p i n s i d e t h e v o l c a n o . Magma (molten rock) chamber. Previous eruptions have formed a cone- shaped exterior. No place for a rock? Deep, deep under the Earth’s crust it is hot enough to melt rock. This molten rock sometimes builds up in chambers and bursts through weak spots in the Earth’s crust. When magma leaves a volcano, it is called lava. Shiprock Shiprock Pinnacle is all that remains of an ancient volcano. It is the hardened core. Just a cliff? The eruption of a volcano can create deep layers of ash, dust, and rock at its base. It changes the landscape. Volcanic debris ranges from dust and ash to rocks the size of houses. Shiprock Pinnacle in New Mexico was once a plug of magma filling the chimney vent of a volcano. Avalanche of rock A volcano erupts with such power that sometimes the eruption destroys a part of the volcano. Huge rocks shoot into the air. S h i p r o c k P i n n a c l e i s n a m e d a f t e r a s h i p a s i t l o o k s a l i t t l e l i k e o n e . Do you think that all rocks look the same? In fact, there are many different kinds of rocks, but they can be divided into three basic types, which are being formed (and destroyed) as you read this book. Making of a rock In the beginning Earth’s first rocks were igneous rocks. These form from molten rock that has cooled and hardened. Chipping away One way sedimentary rock forms is when pieces of rock are carried to the sea where they create huge piles of sediment. After thousands of years these cement together. Molten volcanic rock cools to form igneous rock. S e d i m e n t a r y r o c k S e d i m e n t s a r e 9 Sediment settles on the bottom of seas, rivers, and lakes. b u i l d s u p i n l a y e r s . Getting hotter Rub your hands together and they get hot. Metamorphic rock forms when rocks are squeezed and heated deep under the Earth’s crust. The pressure and heat as granite is forced up causes the development of the metamorphic rock marble. Granite D e e p u n d e r t h e e a r t h , r o c k s a r e b e i n g s q u a s h e d a n d h e a t e d . ROCKING AROUND Over thousands of years, each type of rock can change into one of the others depending on what happens to it, from igneous to sedimentary to metamorphic. Marble s q u a s h e d t o g e t h e r . 10 Igneous rocks form the greatest part of Earth’s rocky crust, but can also be seen in the land around us. A famous igneous rock landscape is the Giant’s Causeway in Northern Ireland. Igneous rock Pumice is an igneous rock from the heart of a volcano. Pele’s hair looks like hair! It forms from sprays of lava. Obsidian has a shiny surface. It contains a lot of glass. Built to last The most common igneous rock is granite. It is incredibly strong, and has been used for building for thousands of years. From hair to glass A volcano produces a great variety of igneous rocks. Just take a look at the three examples shown above. L o n d o n ’ s T o w e r B r i d g e u s e s g r a n i t e . P u m i c e s t o n e i s t h e o n l y f l o a t i n g r o c k . [...]... morphe (meaning form) When rocks are heated or compressed, this type of rock forms A peek at slate The metamorphic rock slate forms from mud and a rock called shale The shale has been squeezed and compressed as mountains are pushed up Slate splits easily into sheets Underground changes One way metamorphic rocks form is when mountains are pushed up out of the Earth’s crust Mountains and hills surround this... sedimentary rock in these hoodoos can be clearly seen The surrounding Attack by sea rock has been washed away Rocks are not as permanent as you may think From driving rain to frothy seas, when rocks are exposed to wind, water, glaciers, or shifts in temperature, changes begin to happen Attack by wind and water Hoodoos are columns of soft sandstone topped by harder rock caps The cap has protected the rock. .. forward, it picks up all sorts of rocks and sediment This forms darker streaks on the surface of the glacier A glacier carves a deep valley as it moves forwards From rock to flour! The sides and base of a glacial valley are covered with plenty of scrapes and scratches This scraping produces fine grains of rock, known as rock flour down the glacier lour is carried on Rock f in lakes eposited in mounta... metals come from the ground Six thousand years ago, many people knew iron as “the metal from the sky”, probably because the first iron people used came from meteorites 31 Using rocks in art Have you ever used a rock to draw? It’s great fun to use chalk and scribble away on a pavement The colours held inside some rocks and minerals have been used by artists for thousands of years Who needs paper? Cave... and brown •For thousands of years, people crushed coloured rocks and mixed the powder with animal fat to make paints The sedimentary rock chalk is messy to use, but it is a fantastic material to use to show how light bounces off an object Gold was extracted from a mineral and used in this 600-year-old painting Cinnabar was first used in ancient China Rich reds The powder of a mineral rock called cinnabar... used for many things, including weapons, tools, containers, and statues •Handaxes, which had no handle, were first used more than 70,000 years ago A helpful handle Hand-held rocks were gradually combined with handles to make axes This stone was held in a length of wood by a tightly bound length of twine h It to takes a long time an d-g rind The handle has been re-made – the original rotted away long ago... From plant to rock Another way in which sedimentary rocks form is by the breakdown of plants As they are buried, they are squeezed together, eventually forming coal 12 Year 1 From plant matter to peat Let’s play Do you like to play in golden sand? This is a sediment Left for thousands of years, it may eventually form sandstone, a sedimentary rock il m es y tak tin alk l as Ch wel As Rocks are continually... rosion c E •Plants add to rock erosion as their roots burrow their way into cracks in rocks •When rocks are broken down where they stand, it is known as weathering 21 of e force Th e r is e laci ag mble rock to cru ugh no Carving a path A glacier is a huge mass of slowmoving ice Born as snow builds up at the top of a mountain, it begins to force its way forward, picking up rocks and boulders as it moves... source 33 Rocks in history A long time ago, somebody somewhere picked up a stone and used it as a tool It was the beginning of something big as people found more and more ways in which to use rocks Just down the road In the past there were no machines to fetch and carry, so people had to use what was available nearby These roofs are covered with slate, taken from a local quarry 34 Rock facts •Rocks have... slate quarry ck Each blo es s of tonn usand eighs tho w Mar ble can be c arv ed Marble is a beautiful metamorphic rock It is mined by being cut into huge blocks with strong cutting wires 14 tat s ue Marble magic in t os Icecream swirls When rocks are heated, parts may begin to melt and run through a “host” rock This makes swirly patterned metamorphic rock The rock is called migmatite A shimmering palace . crust and mantle is made from lots of different rocks, all squashed together. 5 Let’s make a rock Rocks are made up of crystals of minerals. Different amounts of minerals make up different rocks. of a rock In the beginning Earth’s first rocks were igneous rocks. These form from molten rock that has cooled and hardened. Chipping away One way sedimentary rock forms is when pieces of rock. metamorphic. Marble s q u a s h e d t o g e t h e r . 10 Igneous rocks form the greatest part of Earth’s rocky crust, but can also be seen in the land around us. A famous igneous rock landscape is the Giant’s Causeway in Northern Ireland. Igneous rock Pumice